Your last generator Maintenance Run
- Thread starter 3930dave
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Never come across matched plugs...
If the national powers that be think it is a good idea it will become mandatory and all medical facilities will be expected to buy in...
If the national powers that be think it is a good idea it will become mandatory and all medical facilities will be expected to buy in...
daugen
Epic Contributor
I think he means just start it up manually, which all timer controlled units can, the rocker switch is Manual, Off, Auto in most cases. But putting it under a load means manually throwing the service disconnect, which one needs to know what one is doing... On Manual, mine goes to full speed, not the reduced test speed. But I admit I don't throw the big breaker, because my unit is actually used seven or eight times a year for power outages, so it gets run under load fairly regularly. If a whole house backup gen isn't used much, then I bet throwing that big service disconnect several times a year would be a good idea.
On the older residential Generacs I've seen, the main switch was:
Off - for service presumably
Auto - autostart after a fixed delay following line outage
On - you could manually force it to run continuously. Back then, I thought it was for a situation where the grid was bouncing on and off frequently. Just wondering what EPA "protection" has done to this feature.
Rgds, D.
grsthegreat
Super Star Member
manual runs gen, but doesnt switch load over for house.
daugen
Epic Contributor
Dave/3930, is there any rule of thumb for how much load one should put on for test?
I assume more is better, but since almost none of us have a true load meter like they have for batteries, probably have to be
humongous to drawn down 20K..., so if one had a 5kw gen, would putting a single 1500 watt, 13amp heater load on it be enough?
Should one put, say for example, 50% load in order to re-energize the electrical end?
I use two heaters, a 26 amp load on my 7500 portable Westinghouse gen. Makes it work, but not very hard.
How much load is enough?
thanks
I assume more is better, but since almost none of us have a true load meter like they have for batteries, probably have to be
humongous to drawn down 20K..., so if one had a 5kw gen, would putting a single 1500 watt, 13amp heater load on it be enough?
Should one put, say for example, 50% load in order to re-energize the electrical end?
I use two heaters, a 26 amp load on my 7500 portable Westinghouse gen. Makes it work, but not very hard.
How much load is enough?
thanks
Sawyer Rob
Super Member
I believe the manual for my Winco generator says, load generators to 50% load for 30 mins...
That's a pretty good load, for a bigger gen set...
SR
That's a pretty good load, for a bigger gen set...
SR
Started into typing most of this early am, then the day went away on me.....
Short answer - 50% "feels" like enough load. That's a subjective answer, not based on what I call real engineering at my end.
Longer answer - I'm thinking of 2 factors - moisture and the magnetics.
(BTW, I don't consider myself a generator expert - I'd say I fall more into the semi-educated amateur category). That caveat aside, on with my ramble....
I don't like the idea of motor windings staying damp for long periods of time. So, geography comes into play..... if you live in a cold maritime environment, this is a bigger factor than say, somebody living in rural Arizona. So, getting enough heat into the windings during a run matters, in terms of driving out moisture (meaning humidity in the air, not just rainfall exposure.....). In this respect, a 50% load will help, but you can see the YMMV factors.... in Arizona, 50% may be overkill, in Spitsbergen, just barely enough.
Magnetics...... this is where I'd expect big variations between generators. What I mean is behaviour differences between a $99 portable generator, and a $5,000 one. Better to me is being able to go long periods of time w/o requiring a maintenance run (magnetics wise), and also being able to re-energize faster, at lower power levels. Given those engineering variables, 50% load "feels" OK to me on a consumer level portable generator.... but that's just a guesstimate.
On the glass-half-full side of today's problematic gasoline..... most small gens are likely going to be happy (magnetics wise) with how often you need to run most of them to reliably stay ahead of carburetor issues.
In the 10kw+(+) generator area, I don't have enough experience on the magnetics side to place a good guess on appropriate loading.
Rgds, D.
CreekyB
Silver Member
I have been doing generator maintenance on and off for most of my life and part of plant maintenance. Ours have always been diesel, except the few that were natural gas, and the one that was CNG, but only because we had a CNG plant on site that we maintained as well.
Some of the loading/exercising is to keep the engine working properly. As you probably know idling a stored car once a month is better than never starting it but not really keeping it in good shape. You need to exercise all the systems to make sure they are working and keep them in operational state. Basically any load that will idle it up and cause it to work is good. If you are wanting hit a certain amount of load heaters are good. So are compressors. Just make sure that your gen set can handle the inrush of starting a large compressor if you have one. It can be really rough on the motor for the compressor. (Massive lighting loads are also good, not everyone has a few hundred thousand square feet of office space to use as load tho ) You can measure the load using amp meters. If you know your gen set can handle 200 amps total at 220 volts you need to be able to load it at 100 amps on some 220 circuits. Any load is better than no load, you want to see it work, not just sit there and be ready to work.
As for loading keeping the moisture out, or maintaining the magnetics... The magnetic fields are for the most part created under run conditions and induced from one set of windings to another. The iron cores and the windings should be encased in resin to keep dry. If you are getting moisture in the iron cores at a rate significant enough for corrosion periodic run times are not going to keep them dried out. My generator for camping gets exercised right before leaving once every year or three. It works flawlessly, just as good as the ones that I tend to that get exercised weekly. Albeit on a much smaller scale, and minus a phase.
The current place of employment has a few 3 phase generators on site. We have them set to exercise one per week for an hour. 15 minute start up, 30 minute load and 15 minute cool down. We have them set to transfer the whole building UPS systems from city to generator power for that 30 minutes. During these regular automatic exercise cycles the generators and transfer switches are observed.
At the end of the day the main reason you want to exercise your generator has to do with fault detection. Any abnormal run condition or lack or run condition, be it during start up or during transfer/load is best detected while normal power is available so that repairs can be done while normal power is available. It is inevitably harder to source a back up generator or get generator repairs while there is no power as you are probably not the only one in need.
So, how much load? Enough to know that the gen set is going to do it's job when it is needed. How often? Professionally we like to do it weekly but at a minimum monthly.
As for the last generator maintenance run. Oil and fuel filters changed with the oil yearly. Air filters changed when needed. Oil analysis done once a year.
My own personal ones.... Oil changed when it looks bad, never analyzed. Air filters changed when they can't be blown out any more... lol.
Some of the loading/exercising is to keep the engine working properly. As you probably know idling a stored car once a month is better than never starting it but not really keeping it in good shape. You need to exercise all the systems to make sure they are working and keep them in operational state. Basically any load that will idle it up and cause it to work is good. If you are wanting hit a certain amount of load heaters are good. So are compressors. Just make sure that your gen set can handle the inrush of starting a large compressor if you have one. It can be really rough on the motor for the compressor. (Massive lighting loads are also good, not everyone has a few hundred thousand square feet of office space to use as load tho
) You can measure the load using amp meters. If you know your gen set can handle 200 amps total at 220 volts you need to be able to load it at 100 amps on some 220 circuits. Any load is better than no load, you want to see it work, not just sit there and be ready to work.As for loading keeping the moisture out, or maintaining the magnetics... The magnetic fields are for the most part created under run conditions and induced from one set of windings to another. The iron cores and the windings should be encased in resin to keep dry. If you are getting moisture in the iron cores at a rate significant enough for corrosion periodic run times are not going to keep them dried out. My generator for camping gets exercised right before leaving once every year or three. It works flawlessly, just as good as the ones that I tend to that get exercised weekly. Albeit on a much smaller scale, and minus a phase.
The current place of employment has a few 3 phase generators on site. We have them set to exercise one per week for an hour. 15 minute start up, 30 minute load and 15 minute cool down. We have them set to transfer the whole building UPS systems from city to generator power for that 30 minutes. During these regular automatic exercise cycles the generators and transfer switches are observed.
At the end of the day the main reason you want to exercise your generator has to do with fault detection. Any abnormal run condition or lack or run condition, be it during start up or during transfer/load is best detected while normal power is available so that repairs can be done while normal power is available. It is inevitably harder to source a back up generator or get generator repairs while there is no power as you are probably not the only one in need.
So, how much load? Enough to know that the gen set is going to do it's job when it is needed. How often? Professionally we like to do it weekly but at a minimum monthly.
As for the last generator maintenance run. Oil and fuel filters changed with the oil yearly. Air filters changed when needed. Oil analysis done once a year.
My own personal ones.... Oil changed when it looks bad, never analyzed. Air filters changed when they can't be blown out any more... lol.